Nanoparticles have recently attracted significant attention from researchers in a variety of disciplines, due to a wide array of potential applications in the fabrication of nanostructured materials and devices. Semiconductor nanoparticles, such as silicon nanoparticles, are of special interest due to their potential uses in photoluminescence-based devices, doped electroluminescent light emitters, memory devices and other microelectronic devices, such as diodes and transistors. Different methods have been used to synthesize free standing silicon nanoparticles. These methods include laser pyrolysis of silane, laser ablation of silicon targets, evaporation of silicon and gas discharge dissociation of silane.
Amorphous and polycrystalline silicon particles can be produced using argon-silane discharges. See for example, U.S. Pat. No. 4,583,492. However such particles are not suitable for many device applications which require single-crystal particles. Single-crystal nanoparticles have higher carrier velocities due to the absence of grain boundaries or defects leading to potentially better performance. Hence a reproducible reliable method for generating monodisperse, single-crystal nanoparticles is highly desirable for device applications.
Recently single-crystal silicon nanoparticles have been made using very-high-frequency (VHF) pulsed gas plasmas. Using these VHF pulsed gas plasmas it has been reported that single nanocrystals of silicon having diameters of about eight nanometers (nm) may be formed. See, for example, Ifuku et al., Jpn. J. Appl. Phys., 36 (1997), 4031-4034.